Marco Rubio to Iowa to campaign for Joni Ernst

Sen. Marco Rubio (R-Fla.) will travel to Iowa for the first time this year on Monday to stump with GOP Senate candidate Joni Ernst, sources say — one day before Hawkeye State Republicans go to the polls to choose their nominee for the key Senate seat.

Rubio endorsed Ernst, the frontrunner in the GOP contest, earlier this month. Ernst, a state senator, has brought a diverse array of Republican starpower to Iowa: She campaigned with former Alaska Gov. Sarah Palin last month, and 2012 presidential nominee Mitt Romney rallied voters with Ernst at two events earlier Friday.